I used the 24-70 2.8 lens for quite some time. It is an excellent lens. Whether shooting for work or for personal reasons I found the 70mm end to be very limiting. The solution for me was to carry my 80-200 2.8 for those shots beyond 70mm reach. In a fast moving situation that meant two bodies in use at one time. OK, if that is what it takes, that is what I do. Then one day I took the time to research my focal length usage. I discovered that the vast majority (like 88%) of my shots were taken within the 24-120mm range. I was using 2 bodies and two lenses to do that.
I looked into the 24-120 4.0 VR. I had owned the earlier 24-120, and it was a dog, so I was skeptical. I read ever review I could find and watched forum discussions about the lens here at DPReview. There was a fair share of criticism in the forums, usually based upon some statistic in a review. I read reviews, but I make final conclusions based upon what the photos that it makes look like. Since I have been buying form the same Nikon pro dealer for decades, I took a body to the dealer and shot a range of pics to try the lens at different apertures and focal lengths. When I examined the photos in my computer I was impressed, really impressed. The 24-70 was a bit better in some ways, but n to enough mean anything in practical use (that is what I care about). I bought the 24-12/4.0 VR.
I use it for about four months and then sold the 24-70/2.8 Now it accounts for well over 80% of the photos I take. It has some distortion at 24mm, but I find it early correctable. I usually batch correct in Capture NX2 and then export the file to Aperture 3. Do I miss the f/2.8? No, i don't. The VR makes up for it. Do I miss the shallow depth of field at 2.8. Rarely, and I work around it when I need to.
A year ago I replaced my 17-35/2.8 with the 16-35/4 VR. No regrets. Recently, when shooting outdoors and in need of a lens over 120mm I use the 70-300 VR. No regrets. I still use the 80-200 2.8 at times, but not often.
My ready top go bag has a D700 with MBD10, a 16-35/4.0 VR, a 24-120/4.0 VR and a 70-300 4.5-5.6 VR in it. It is a fabulous kit when it comes to making good images for practical use.
If I could only have one lens it would be the 24-120/4.0 VR!
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Richard Weisgrau
http://www.weisgrau.com
Author of
The Real Business of Photography
The Photographer's Guide to Negotiating
Selling Your Photography
Licensing Photography